Means for minimizing inductive interference.



c. F. SCOT-T.

MEANS FOR MINIMIZING INDUCTIVE INTERFERENCE.

APPLICATION FILED JAN- 2- I915.

' 1,196,302, I PatentedAug. 29,1916.

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CHARLES E. SCOTT, OF NEW HAVEN, CONNECTICUT, ASSIGNOR T0 WESTINGHOUSEELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented Aug. 29, 1916.

Application filed January 2, 1915. Serial No. 172.

To all whom it may concern:

.Be it known that I, CHARLES F. SCOTT, a citizen of the United States,and a resident of New Haven, in the county of New Haven and State ofConnecticut, have invented a new and useful Improvement in Means forMinimizing Inductive Interference, of which the following is aspecification.

My invention relates to improvements in means whereby electric currentflow may be substantially confined to certain conducting paths inpreference to other paths whlch may be of lower impedance and which maybe electrically connected in parallel relationship therewith.

More particularly, my invention, relates to improvements in meanswhereby the return flow of trolley currents of a railway system may besubstantially confined to the track rails in preference to ground orearth return. As fully explained in my patent application, Serial No.170, filed concurrently herewith and assigned to the WestinghouseElectric & Manufacturing Company, by thus confining the return flow oftrolley currents to the track rails, inductive disturbances which arisefrom currents flowing in the railway system, and which may be imposedupon an intelligence-transmission circuit disposed in proximity thereto,may be greatlv minimized. Moreover, electrolytic corrosion of gas mains,water mains. etc., which might result from the flow through earth ofcurrents that originate in railway systems, is substantially avoided.

To this end. I haveproposed that series transformers be inserted atspaced intervals in a railway system, the primary windings of thetransformers being connected across insulating joints and inseries-circuit relationship with the trolley conductor, and thesecondary windings. having preferably the same number of turns as theaforementioned primary windings, being connected at corresponding pointsin the rail circuit and across insulating joints that divide the railcircuit into a plurality of track sections which are insulated from oneanother. By this means, electromotive forces are impressed, atintervals, upon the track rails, thereby compensating for comprising asingle rail or a pair of rails,

is substantially high, under all conditions, it is advisable, when othertrack rails are available, to interconnect electrically all of thetracks in such a manner that they may be used concurrently as paths forthe return flow of the trolley currents.

By means of my present invention, I substantially decrease the impedanceof a track, which is paralleled and adjacently disposed to other tracks,by interconnecting certain portions thereof in parallel relationship,and, at the same time, I insure confinement of the trolley currents tothese tracks by inductively interlinking them with the trolleyconductor.

For a better understanding of the nature and scope of my invention,reference may be had to the following description and the accompanyingdrawing in which the single figure is a diagrammatic representation of arailway system embodying a form of my invention.

Referring to the drawing, a source of power supply 1, shown as asingle-phase alternator, is connected to trolley conductors =2 and 3,and to the track rails 4t and 5,

which are associated respectively with the aforementioned trolleyconductors. In each trolley conductor 2 and 3, I insert, at spacedlntervals, series transformers 6, primary windings 7 thereof beingconnected in series-circuit relationship with the trolley conductors,and secondary windings 8 being connected across insulating joints 9disposed at corresponding points in the track rails 4t and 5. As shownin the drawing, each track 4 and 5 comprises two rails 10 which are moreor less in contact with the earth, as is usual with all railway systems.

As explained above, a track comprising a single rail or a pair of railshas considerable impedance, and, inasmuch as the two tracks 4 and 5 aredisposed adjacent to each other, it is desirable to interconnect them insuch a manner as to lower the impedance of the path for the return flowof the trol ley currents. At the same time, it is desirable to minimizethe inductive disturbances upon intelligence-transmission circuits 11,shown as telegraph circuits, which are so disposed as to be under theinductive influences arising from the currents flowing in the railwaysystems.

To this end, the tracks 4 and 5 are electrically interconnected by meansof bonds 12 extending between alternate sections of the tracks, as shownin the drawing. To illustrate, assume that the transformers 6 are spacedone mile. apart in each railway system. For the mile intervening betweenthe source of power supply 1 and the first series transformers insertedin the railway systems, the tracks 4 and 5 are electrically independentof each other. For the mile intervening between the first and secondseries transformers, the tracks 4 and 5 are electrically interconnectedin parallel relationship by means of the bonds 12. Similarly, alternatesections of the railway systems along the entire right-of-way areinterconnected. As a result, current flowing from a moving vehicle uponone of the railway systems will traverse a single track in alternaterail sections, and all of the tracks connected in parallel relationship,in the other rail sections. Consequently, the impedance of the returnconductor for the trolley currents is'considerably reduced, and thetracks 4 and 5 are so interconnected that unduly high differences ofpotential cannot exist between them.

In commercial installations, it may be necessary to compensate for theirregular spacing of the intelligence-transmission conductors 11relative to the railway systems. For this reason, I have shown theprimary and secondary windings of the transformers 6 as provided with aplurality of taps 13 by means .of which the ratios of the turns of theprimary and secondary windings may be regulated so as to force certaincurrents to flow through the earth. These earth currents may be soadjusted as to induce electromotive forces in either direction in thetelegraph conductors 11, and hence, are utilized for correcting orneutralizing certain other electromotive forces which may be inducedtherein by reason of the unequal I spacing of the telegraph circuit fromthe trolley circuits and the track circuits.

While I have shown my invention as applied to two railway systems, itwill be understood that it may be utilized with any number of railwaysystems or tracks which may be paralleled along the same right-ofway.

Iclaim as my invention:

1. A railway system comprising a source of current supply, a trolleyconductor connected thereto, a conductor comprising a plurality ofparallel tracks, spaced insulating joints correspondingly inserted ineach track to form a series of rail sections insulated from one another,transformers to in terlink inductively the trolley conductor with someof said tracks, and conducting bonds to electrically connect alternaterail sections of all said tracks.

2. A railway system comprising a source of current supply, a trolleyconductor connected thereto, a conductor comprising a plurality oftracks, spaced insulating joints correspondingly inserted in each trackto form a series of rail sections insulated from one another,transformers to inductively interlink said trolley conductor and some ofsaid tracks, and conductors for electrically connecting in parallelrelationship alternate rail sections of all said tracks.

3. A railway system comprising a source of current supply, a trolleyconductor connected thereto, a conductor comprising a plurality oftracks, spaced insulating joints inserted in each track to provide aseries of rail sections insulated from one another, electricalconnections to connect alternate rail sections of all the tracks inparallel relationship, and means to inductively interlink some of thetracks with the said trolley conductor. v

4. A railway system comprising a source of current supply, a trolleyconductor connected thereto, a conductor comprising a plurality oftracks, spaced insulating joints inserted in each track to provide aseries of rail sections insulated from one another, electricalconnections extending between alternate rail sections of all the tracks,and transformers having primary windings inserted at intervals and inseries-circuit relationship with said trolley conductor and secondarywindings connected in shunt to the insulating joints in some of thetracks.

5. A system of distribution comprising a source of current supply, aconductor connected to one terminal thereof, a plurality of conductorsconnected to the other terminal, said second conductors constituting aseries of conducting sections insulated from one another, means servingto impress electromotive forces. at intervals, upon some of said'secondconductors, and means for connecting, in parallel relationship, certainsections of all of said second conductors.

6. A system of distribution comprising a source of current supply, aconductor connected to one terminal thereof, a plurality of conductorsconnected to the other terminal, each of said second conductorscomprising a series of conducting sections insulated from one another,means serving to inductively subscribed my name this 23rd day of Dec,

intgrlink sitid fi'st conducfior with fsomel of 1914. sai secon conuctors an means or e 00-- trically connecting, in parallel r elationshiCHAS SCOTT 5 alternate conducting sections of all of said Witnesses:

second conductors. B. B. Hnms,

In testimony whereof, I have hereunto M. C. Mnnz.

